from random import randint
import datetime
#might as well use the datetime we made in main for consistency
from main import DATETIME_STR

# updates the guid given in two places with the RSS file, essential for letting readers know
# a new picture has been published

# refrence: https://cyber.harvard.edu/rss/rss.html#ltguidgtSubelementOfLtitemgt

# also updates pubDate and lastBuildDate
# finay, updates the image name as well

def update_rss_feed(rss_file_name):
    rss_file = ""
    
    with open(rss_file_name, "r") as f:
        rss_file = f.read()                           
    element_list = rss_file.split('\n')

    items = []
    for el in element_list:
        if "link" in el:
            items.append(el)
        if "guid" in el:
            items.append(el)
        if "enclosure" in el:
            items.append(el)
        if "<lastBuildDate>" in el:
            items.append(el)
        if "<pubDate>" in el:
            items.append(el)

    guid_items = []
    for el in items:
        if "https://onecatper.day#" in el:
            guid_items.append(el)
    
    hash_located_at = []
    for el in guid_items:
       hash_located_at.append(el.index('#'))
    
    CLOSING_TAG_LENGTH = 7
    as_char_list = list(items[2])
    for i in range(hash_located_at[0] + 1, len(as_char_list) - CLOSING_TAG_LENGTH):
        as_char_list[i] = str(randint(0, 9))
    new_guid_link_one = "".join(as_char_list)

    as_char_list = list(items[4])
    for i in range(hash_located_at[1] + 1, len(as_char_list) - CLOSING_TAG_LENGTH):
        as_char_list[i] = str(randint(0, 9))
    new_guid_link_two = "".join(as_char_list)
    
    split_file = rss_file.split("\n")
    old_guid_links = []

    for element in split_file:
        if "https://onecatper.day#" in element:
            old_guid_links.append(element)

    # preppring strings for replacement of the old strings

    # cat image stored in img/
    old_img_link = items[-1].split(" ")
    old_cat_image = old_img_link[-1].split("\"")
    old_cat_image_url = old_cat_image[1]
    new_cat_image_url = f"https://onecatper.day/img/cat{DATETIME_STR}.jpg"

    # storess dates and times in the rss.xml file, needs to be updated for feed to update
    old_last_build_date = items[1]
    old_pub_date = items[3]
    # date and time need to be a specific format
    # don't want to use constant for this, it needs to be formated
    rss_date = datetime.datetime.strftime(datetime.datetime.now(), "%a, %d %b %Y %H:%M:%S -0500")
    # create new date/time links for feed
    new_last_build_date = f"\t\t<lastBuildDate>{rss_date}</lastBuildDate>"
    new_pub_date = f"\t\t\t<pubDate>{rss_date}</pubDate>"

    # replace what is necessary to make the feed update
    rss_file = rss_file.replace(old_guid_links[0], new_guid_link_one)
    rss_file = rss_file.replace(old_guid_links[1], new_guid_link_two)
    rss_file = rss_file.replace(old_cat_image_url, new_cat_image_url)
    rss_file = rss_file.replace(old_last_build_date, new_last_build_date)
    rss_file = rss_file.replace(old_pub_date, new_pub_date)

    # write the changes to disk
    with open(rss_file_name, "w") as f: 
        f.write(rss_file)

update_rss_feed("rss.xml")